The usage of very small electrical conductors has created connecting and terminating problems which can not be adequately handled by the electrical connectors which were designed to electrically connect and terminate larger wires. One problem which is created by the use of small conductors, is that the very small conductors are physically difficult to handle or manipulate with respect to the usual connector components. Another difficulty associated with the small conductors relates to the relatively disproportionate strength of the conductor insulating material which is generally provided about the fine wire. The foregoing factors are further complicated in situations wherein it is desirable to interconnect fine wire conductors of different diameters or, to connect fine wire conductors to printed circuit conductive paths.
One solution to the problem of terminating fine wire is described in U.S. Pat. No. 3,249,908. The electrical connector disclosed includes a post member adapted to be wedged within an eyelet or sleeve member to entrap one or more conductors therebetween and terminate such to the conductive material of the members. Either the post or the eyelet member is provided with small serrations extending radially about the member which operate to remove the insulation from conductors. As a basic part of the invention, the post and eyelet members are provided with distinctly different tapers, with that of the eyelet member being larger. This feature has been discovered to permit termination of different size conductors by the same post and eyelet assembly at the same time and to preclude accidental snipping off of conductors through the provision of an inherent strain relief to the conductor as it enters into the eyelet member and is terminated. Additionally, this feature permits a wide variation in insertion force since the post can effectively terminate a conductor without pinching it off even though forced into the eyelet well beyond the point necessary for termination. The conductor terminated is left in a configuration defined by the difference in taper and which is itself tapered out from a point of near normal thickness to a thinned end with a broad area of contact interface being defined.
Although the above-referenced patent discloses a viable manner in which to terminate fine wires, several problems are associated therewith. As the wire is terminated, the cooperation of the serrations with the walls of the sleeve member trap the conductors therebetween, thereby holding the conductors in position. However, if a force is applied to a respective conductor, the force will be transmitted through the conductor to the point at which the serrations and walls are in cooperation with the conductors. As the conductors have been deformed in this termination zone, the conductors are relatively weak in this zone. Consequently, a force applied to the conductors may result in the failure of the conductor in the termination zone, which causes the entire electrical connection to be ineffective. In order to eliminate the strain applied to the conductors in the termination zone, it would prove beneficial to have a strain relief zone provided proximate the termination zone.
Another problem associated with the device disclosed in the prior art relates to the fact the no cutting means is provided to cut off the ends of the cable. In other words, if the fine wire is not to be terminated in a daisy chain fashion, there is no means to remove the excess wire from the termination. Therefore, prior to the termination of the wire, the wire must be cut to the appropriate length and inserted into the sleeve of the connector. Using this method the positioning of the wire is critical in order to insure that a positive electrical connection is effected. It would therefore be beneficial to provide the eyelet with a cutting surface which would cut the wire to the appropriate length concurrently with the electrical termination of the wire.